how can I put manually external dimensions of a 2d draw

I have used DesignCAD by IMSI to load a simple draw designed from Sketchup. After load the the 2d draw in DesignCAD (the draw was always the pattern of a bed headboard to be then compiled and used by a big sewing machine), I selected the draw, go to INFO BOX and put the real external dimensions of the lines the would be sewed by machine. But my question is, how to put the external dimensions of the draw? Example, I need the machine to sew the upholstery with this dimension: 1620 x 1030 mm. Can anyone help?

in the right of DesiGNCAD you have the bounding box. can librecad make this?